Phantom dosimeters examined by NMR analysis: a promising technique for 3-D determinations of absorbed dose.
Fricke-infused agarose gels examined by nuclear magnetic resonance (NMR) analysis are inspected, and their response to gamma-rays, thermal neutrons and protons, at radiotherapy dose levels, is examined. The gel composition is chosen with attention to the tissue equivalence for the radiation fields of interest; this problem is crucial, in particular, for thermal neutrons. The feasibility of three-dimensional determination of absorbed dose in Fricke-gel phantoms is investigated, and the possibility of employing the technique in conformal therapies, such as boron neutron capture therapy (BNCT) and proton therapy, is tested. Isodose curve determination in a cylindrical gel phantom exposed to thermal neutrons is presented. A method for depth-dose profiling in tissue exposed to protons is described, and some results are reported which show that the depth-dose data are determinable with millimetric precision. Results obtained with a spectrophotometer from gel augmented with a metal indicator are reported and discussed also. These results show the possibility of obtaining a very sensitive dosimetry technique consisting of spectrophotometric analysis of such a Fricke-gel.
Gambarini
G
G
Dipartimento di Fisica dell'Università, Milano, Italy.
Monti
D
D
Fumagalli
M L
ML
Birattari
C
C
Salvadori
P
P
D000042:Absorption; D005720:Gamma Rays; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009502:Neutrons; D019047:Phantoms, Imaging; D011522:Protons; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D011879:Radiotherapy Dosage
D011522:Protons